KR20050014129A - Session Initiation Protocol server and SIP message handling method - Google Patents

Abstract

PURPOSE: An SIP(Session Initialization Protocol) server and a message processing method thereof are provided to operate the SIP server as a redirect server if a risk of system overload may occur while the SIP server is operated as a proxy server if system efficiency is low, thereby preventing system overload while suppressing a call processing delay. CONSTITUTION: A message receiver(200) receives an SIP message including a receiver identifier from an originator. A mode setting unit(210) sets the first mode which carries out a proxy server function based on a kind of the received SIP message and a system efficiency, and sets the second mode which executes a redirect server function. A proxy server unit(220) perceives a receiver position based on the receiver identifier in the first mode, and transmits the SIP message to the perceived receiver position. A redirect server unit(230) perceives the receiver position based on the receiver identifier in the second mode, and sends the perceived position information to the originator.

Description

Session Initiation Protocol server and SIP message handling method

The present invention relates to a Session Initiation Protocol (SIP) server that handles calls of Internet telephones, and more particularly, to a proxy server and a redirect server that process SIP messages.

SIP is a very simple, text-based application layer control protocol that allows one or more participants to create, modify, and terminate a session together. These sessions include teleconferences over the Internet, telephone calls, visits, event notifications, instant messaging, etc. SIP is independent of the underlying packet protocols (TCP, UDP (User Datagram Protocol), ATM, X.25). .

SIP was designed after text-based Simple Mail Transfer Protocol (SMTP) and HTTP. SIP is based on a client / server architecture where clients initiate a call and the server responds to the call. SIP follows these existing text-based Internet standards, making troubleshooting and network debugging easier.

Conventional SIP servers that process SIP messages include proxy servers and redirect servers.

The conventional proxy server is a call processing server that receives a SIP request message from a calling party, finds and delivers the location of the next called party, and receives a response message from the called party and delivers the message to the calling party.

A conventional redirect server is a server that, upon receiving a SIP request message, maps the address in the request message to a new address and sends the result back to the originator. Unlike a proxy server, it does not initiate a SIP request, does not receive a response message, and informs the sender of only the address where the next call is to be made.

Conventional SIP servers do not take into account system efficiency when processing SIP messages, but are initially initially designated as either a proxy server or a redirect server to process SIP messages. The proxy server can handle SIP messages well when the system efficiency is low. However, because of the overload when the system efficiency is high, call delay occurs when processing all SIP request and response messages.

In the case of the conventional redirect server, by providing the location information on the system request message as a response message, it performs a call processing function while reducing the system load, but has a disadvantage in that the SIP message cannot be delivered to the next node. Therefore, when the SIP server is initially installed, it is advantageous to estimate the frequency of SIP calls and to install the redirect server where the efficiency is high and the proxy server is installed where the efficiency is low. However, since the frequency of calls is variable, it is difficult to initially specify a SIP server.

The technical problem to be achieved by the present invention is to operate a SIP server as a proxy server when the system efficiency is low, and to operate as a redirect server when the system efficiency is high, SIP server and SIP to improve the processing efficiency of SIP messages To provide a message handling method.

Another technical problem to be solved by the present invention is to operate a SIP server as a proxy server when the system efficiency is low, and to operate as a redirect server when the system efficiency is high, thereby processing SIP messages to improve the processing efficiency of SIP messages. A computer readable recording medium having recorded thereon a program for executing the method on a computer is provided.

1 is a diagram illustrating an embodiment of a VoIP system including a SIP server according to the present invention;

2 is a block diagram of a SIP server according to the present invention;

3 shows a SIP server according to the invention in terms of process, and

4 is a diagram illustrating a flow of a SIP message processing method according to the present invention.

In order to solve the above technical problem, an embodiment of a SIP server according to the present invention, the message receiving unit for receiving a SIP message including a destination URI (Uniform Resource Identifier) from the calling party; A mode setting unit configured to set a first mode performing a proxy server function and a second mode performing a redirect server function based on the received SIP message type and system efficiency; A proxy server unit configured to determine a location of a called party based on the called party URI in the first mode and to transmit the SIP message to the identified called party location; And a redirect server unit for identifying the location of the called party based on the called party URI in the case of the second mode and transmitting the identified location information of the called party to the calling party.

Preferably, the SIP message is divided into a predetermined request message and a predetermined response message, and the mode setting unit includes the second mode when the type of the received SIP message is the request message and the system efficiency is equal to or greater than a predetermined reference value. Set.

In order to solve the above technical problem, an embodiment of a method for processing a SIP message according to the present invention includes: receiving a SIP message including a called party URI from a calling party; Setting a first mode performing a proxy server function and a second mode performing a redirect server function based on the type of the received message and the efficiency of the system; Determining a location of the called party based on the called party URI; Transmitting the SIP message to the identified called party location in the case of the first mode; And transmitting the identified location information of the called party to the calling party in the second mode.

Preferably, the SIP message includes a predetermined request message and a predetermined response message, and the mode setting step includes: a second message if the SIP message is the request message and the system efficiency is equal to or greater than a predetermined reference value; Setting a mode.

According to the present invention, if the system efficiency of the SIP server is increased and there is a risk of overloading the system, the SIP server is operated as a redirect server, and if the efficiency of the SIP server system is low, the SIP server is operated as a proxy server. This prevents system overload and delays in call processing.

Hereinafter, with reference to the accompanying drawings will be described in detail a SIP server and SIP message processing method according to the present invention.

1 is a diagram illustrating an embodiment of a VoIP system including a SIP server according to the present invention.

Referring to FIG. 1, the VoIP system includes a calling terminal 100, a called terminal 120, a SIP server 110, a domain name server 130, and a location server ( 140).

The calling terminal 100 and the called terminal 120 are provided with a desktop PC phone, a notebook connected via a wireless LAN, a PDA and an IP Hand-Phone, a mobile communication terminal via a mobile switch center (MSC), and an exchange. There are telephone terminals.

The SIP server 110 performs a function of a proxy server or a redirect server based on the type of SIP message received from the originating terminal apparatus 100 and the system efficiency of the SIP server 110. When the SIP server 110 performs the function of a proxy server, the SIP message may be a request message, the efficiency of the SIP server 110 may be 70% or less, and the SIP message may be a response message. When the SIP server 110 performs the redirect server function, the SIP message is a request message and the efficiency of the SIP server 110 is 70% or more. The criterion of SIP system efficiency to classify server functions may be 70% or less, or more, depending on the situation of each system.

When the SIP server 110 performs the function of a proxy server, when the SIP server 110 receives a request message for call setup from the calling terminal 100, the SIP server 110 directly sends a request message to the called terminal 120. Transmits, and when the response message is received in response to the request message, transmits the response message to the calling terminal device (100).

When the SIP server 110 performs the function of a redirect server, when the SIP server 110 receives a request message for call setup from the calling terminal 100, the SIP server 110 determines the location of the called terminal. The called party location information is transmitted to the calling terminal device 100. In other words, it does not directly transmit the request message or receive the response message.

The domain name server 130 and the location server 140 are used by the SIP server 110 to determine the location of the called terminal 120. Since the called party address of the SIP message is mainly a Uniform Resource Indentifier (URI), the SIP server 110 determines the called party IP address from the domain name server 130 based on the called party URI, or the location server 140. From the grasp of the position of the SIP server 110 to which the destination terminal device 120 belongs.

2 is a block diagram showing a detailed configuration of a SIP server according to the present invention.

Referring to FIG. 2, the SIP server according to the present invention includes a message receiving unit 200, a mode setting unit 210, a proxy server unit 220, and a redirect server unit 230.

The message receiver 200 receives a SIP message from the calling terminal device 100. The SIP message consists of a request message and a response message. The request message includes a RESISTER message that registers the terminal location, an INVITE message that initiates the call, an ACK message that confirms the call connection, a CANCEL message that cancels the call connection, a BYE message that terminates the call, and information without changing the status of the call. There is an INFO message. The response message contains a STATUS message indicating the progress of the call. The message receiver monitors the arrival of the SIP message.

The mode setting unit 210 determines the type of the received SIP message and the efficiency of the system, and sets the first mode performing the proxy server function or the second mode performing the redirect server function. The type of the SIP message is divided into a request message and a response message. Since the SIP message type is the same as described above in the message receiving unit, a detailed description thereof will be omitted.

The mode setting unit 210 selects the first mode when the received SIP message is a request message and the system efficiency of the SIP server 110 is equal to or less than a preset reference value. The mode setting unit 210 selects the first mode regardless of system efficiency if the received SIP message is a response message. The mode setting unit 210 selects the second mode if the received SIP message is a request message and the efficiency of the system is greater than or equal to a preset reference value.

The efficiency of the system means the efficiency of the central processing unit (CPU) of the SIP server 110. The higher the efficiency of the system, the more heavy the load on the system. In other words, when the CPU's maximum processing capacity is 1, the CPU throughput is 1, and the system efficiency is 100%. If the CPU throughput is 0.7, the system efficiency is 70%. System efficiency, which is a criterion for distinguishing the first mode and the second mode, is preset in accordance with the situation of each system. The mode setting unit judges that there is a risk of overloading the system if it is more than 70% of the system efficiency, and there is no possibility of overloading if it is less than that. The efficiency of the system is preferably the system efficiency at the time when the message receiver 200 receives the SIP message.

When the SIP server 110 performs the function of a proxy server, the CPU throughput of the SIP server 110 is increased, so the system efficiency is high. When the SIP server 110 performs the redirect server function, the CPU throughput of the SIP server 110 is low. Is lowered. Therefore, the message receiving unit 200 selects a server function according to the system efficiency at the time of receiving the SIP message, so that the efficiency of the system is too high, the overload occurs and the SIP message processing time is delayed due to the overload. You can prevent it.

The proxy server unit 220 is a component that processes the SIP message when the mode setting unit 210 is set to the first mode that performs the function of the proxy server. The first mode is set when the SIP message is a request message and the system efficiency is equal to or less than a predetermined predetermined reference value and when the SIP message is a response message. Hereinafter, the configuration and function of the proxy server unit 220 will be described by dividing the SIP message is a request message and the response message.

First, the configuration and function of the proxy server unit 220 when the SIP message is a request message will be described. The proxy server 220 includes a first message processing unit 222, a first destination location detecting unit 224, and a first message transmitting unit 224.

The first message processor 222 generates an incoming process for interpretation and error processing of the received SIP message, and stores an identifier of the generated process, a branch parameter included in the SIP message, a CSeq method, and a called party address. Based on the stored information, the message receiving unit 200 receives a message different from the SIP message currently being processed. When the same message is received, the first message processing unit does not generate an incoming process. The process will be described in detail with reference to FIG. 3.

The first called location detecting unit 224 is based on the called party URI of the received SIP message, the SIP server location or called party of the called party from the domain name server (DNS) 130 or the location server (Location Server) 140. Figure out the IP address. Uniform Resource Identifiers (URIs) are means for recognizing any one of such content, whether it is a page of text, a video clip or sound clip, a still picture or movie, or a program. The most common form of URI is a web page address, or URL, which is a special form and subset of URIs. The location server contains the location information of the called SIP server.

The first message transmitting unit 226 transmits the SIP message received by the message receiving unit 200 to the location of the called terminal terminal 120 identified by the first called location detecting unit 224. In detail, the first message transmitter 226 generates an originating process for performing an originating process of the SIP message, and stores identification information of the originating process, a branch parameter of the SIP message, and a CSeq method. When the message receiving unit 200 receives the response message in response to the request message, the first message processing unit 222 uses the branch parameter and the CSeq method to check whether the received response message is a valid response to the request message. To retrieve a stored outgoing process. In other words, if there is a request message corresponding to the branch parameter of the response message and the CSeq method, the response message is a legitimate response. The reception of the response message will be described in detail below.

Next, the configuration and function of the first message processing unit 222 when the SIP message is a response message will be described. The proxy server 220 includes a first message processing unit 222, a first destination position detecting unit 224, and a first message transmitting unit 226. When the message receiving unit 200 receives the response message from the called party 120 in response to the request message, the proxy server unit 220 transmits the response message to the originating terminal device 100 of the request message.

The first message processor 222 uses the branch parameter and the CSeq method of the received response message to confirm the existence of the request message corresponding to the response message. Since the first message transmitter 226 stores the identifier of the originating process, the branch parameter of the request message, and the CSeq method stored after transmitting the request message, the first message processor 222 stores the branch parameter and the CSeq method of the response message. You can search for the origination process by using. That is, the first message processor 222 determines whether a branch parameter of the response message and a request message corresponding to the CSeq method exist. If the request message corresponding to the response message does not exist, the first message processing unit 222 generates an error response message.

The first called location detecting unit 224 detects the location of the calling terminal 100 that has transmitted the request message corresponding to the response message. Since the SIP server 110 has already received the request message before the response message is received and the SIP message includes the originating address, the first destination location detecting unit 224 may determine the originating terminal device from the request message corresponding to the response message. Determine the location of 100.

The first message transmitter 226 transmits the response message to the calling terminal apparatus 100 of the identified request message. If there is no request message corresponding to the response message, the first message transmitter 226 transmits an error response message generated by the first message processor 222 to the calling terminal 100.

In the above description, the proxy server 220 performing the proxy server function in the first mode is divided into a case in which a request message and a response message are received. Hereinafter, the case of the second mode will be described.

The redirect server 230 is configured to process the SIP message when the mode setting unit selects the second mode to perform the function of the proxy server. The second mode is set when the SIP message is a request message and the system efficiency is equal to or greater than a predetermined predetermined reference value. The redirect server 230 includes a second message processor 232, a second destination location detector 234, a message generator 236, and a second message transmitter 238.

The second message processing unit 232 generates an incoming processor for interpreting and error processing a SIP message, and stores an identifier of the generated incoming process, a branch parameter included in the SIP message, a CSeq method, and an originating address. The message receiver 200 examines the same message as the SIP message currently being processed and does not receive the same message based on the stored information.

The second destination location detecting unit 234 grasps the SIP server location or the destination IP address of the called party from the domain name server 130 or the location server 140 based on the called party URI of the received SIP message. The message generator 236 generates a response message including the identified called party location information. The second message transmitter 238 transmits the response message generated by the message generator 236 to the calling terminal device. Since the redirect server unit 230 does not directly transmit the request message to the called party and does not need to receive the response message, it is necessary to generate the originating process and store the branch parameter and the CSeq method of the SIP message like the proxy server unit 220. I never do that.

3 shows a SIP server according to the invention in terms of process.

Referring to FIG. 3, the SIP server 110 includes a SIP message processing process 300, a proxy server core process 310, a proxy incoming process 320, a proxy originating process 330, and a redirect server core process 340. ) And the redirect incoming process 350.

The process is a program that executes independently. In the present invention, the process is implemented using the specification and description language (SDL) language recommended for communication system design in ITU-T. SDL processes communicate asynchronously with each other through signals. In SIP, items such as Via, To, From, Call-ID, CSeq, Contact, and Max-Forward exist. The branch parameter is generated with a unique value for each request message when the request message is generated.

The SIP message processing process 300 monitors SIP messages arriving at the SIP server and receives the SIP messages. In addition, the SIP message processing process 300 determines the type of the received SIP message, investigates the system efficiency of the SIP server 110, and selects a mode for performing a proxy server function or a mode for performing a redirect server function. .

When the SIP server performs a proxy server function, the proxy server core process 310 generates a proxy incoming process 320 and a proxy originating process 330. The proxy server core process 310 also stores the identifier of the generated called process, the branch parameter of the received SIP message, the CSeq method, and the originating address. After storing, the proxy server core process 310 identifies the called party's location from the domain name server 130 or the location server 140 based on the called party's URI of the SIP message, and the SIP message is identified to the called party's location. Send it. After the transmission, the proxy server core process 310 stores the identifier of the generated originating process, the branch parameter of the transmitted SIP message, and the CSeq method. The identifier of the stored originating process or the like is used to retrieve the request message corresponding to the response message.

Proxy incoming process 320 decrypts the received SIP message and handles errors related to the SIP message. The proxy originating process 330 periodically requests the called party to send a response message. When the response message is received, the message retransmission timer of the proxy originating process is released.

The redirect server core process 340 generates the redirect incoming process 350 and stores the identifier of the incoming process, the branch parameter of the received SIP message, the CSeq method, and the originating address. In addition, the redirect server core process 340 determines the called party's location from the domain name server or the location server based on the called party's URI of the SIP message, and then transmits the identified called party's location information to the calling party terminal device 100. . The redirect incoming process 350 performs decryption and error handling of the received SIP message.

4 is a diagram illustrating a flow of a SIP message processing method according to the present invention.

Referring to FIG. 4, the message receiving unit 200 receives a SIP message from the calling party 100 (S400). SIP messages are divided into request messages or response messages. If the received SIP message is a request message (S402) and the system efficiency of the SIP server is 70% or less (S404), the first message processing unit 222 generates an incoming process for performing decryption and error processing of the SIP message (S406). ). In addition, the first message processing unit 222 stores the generated ID of the incoming process, the branch parameter of the SIP message, the CSeq method and the calling party address (S408).

The first called location detecting unit 224 determines the called party location from the domain name server 130 or the location server 140 based on the called party URI of the SIP message (S410). The first message transmitter 226 generates an originating process for transmitting the SIP message (S412), and stores the identifier of the generated originating process, the branch parameter of the SIP message, and the CSeq method (S416). The first message transmitter 226 transmits the SIP message to the identified called party location (S414). The originating process periodically sends a retransmission message to the called party until a response message to the request message is received.

If the received SIP message is a response message (S402), the first message processing unit 222 checks whether a request message corresponding to the response message exists based on the branch parameter of the received response message and the CSeq method (S428). If there is a request message corresponding to the response message (S430), the first message processor 222 releases the timer for retransmission of the message in the originating process generated for the request message (S432), and the request message corresponding to the response message is released. If it does not exist, generates an error response message (S434).

The first called location detecting unit 224 detects the location of the calling terminal 100 of the request message corresponding to the response message. The first message transmitter 226 transmits the response message or the error response message to the calling terminal apparatus 100 that has transmitted the request message (S436).

If the received SIP message is a request message (S402) and the system efficiency of the SIP server is 70% or more (S404), the second message processing unit 232 generates an incoming process for performing SIP message decryption and error processing (S418). In operation S420, the identifier of the called party, the branch parameter of the SIP message, the CSeq method, and the calling party address are generated.

The second called location detecting unit 234 determines the called party location from the domain name server 130 or the location server 140 based on the called party URI of the SIP message (S422). The message generator 236 generates a response message including the determined called party location information (S424). The second message transmitter 238 transmits the response message generated by the message generator 236 to the calling party (S426).

The invention can also be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

The foregoing descriptions are merely illustrative of preferred embodiments, and the present invention is not limited to the above-described embodiments and can be variously changed within the scope of the appended claims. For example, the shape and structure of each component specifically shown in the embodiment of the present invention may be modified.

According to the present invention, if the system efficiency of the SIP server is increased and there is a risk of overloading the system, the SIP server is operated as a redirect server, and if the efficiency of the SIP server system is low, the SIP server is operated as a proxy server. This prevents system overload and delays in call processing. Since the frequency of calls is variable, the difficulty of installing a proxy server or redirect server is also solved.

Claims (12)

A message receiving unit for receiving a Session Initiation Protocol (SIP) message including a called party identifier from a calling party; A mode setting unit configured to set a first mode performing a proxy server function and a second mode performing a redirect server function based on the received SIP message type and system efficiency; A proxy server unit configured to determine a location of a called party based on the called party identifier in the first mode and to transmit the SIP message to the identified called party location; And And a redirect server unit for detecting the location of the called party based on the called party identifier in the second mode and transmitting the identified location information of the called party to the calling party. The method of claim 1, The SIP message is divided into a predetermined request message and a predetermined response message, And the mode setting unit sets the second mode if the type of the received SIP message is the request message and the system efficiency is equal to or greater than a predetermined reference value. The method of claim 1, The proxy server unit, A first called location detection unit for detecting a location of a called party from a location server including location information of a domain name server or a SIP server based on the called party identification; And And a first message transmitter for transmitting the received SIP message to the determined called party location. The method of claim 1, The redirect server unit, A second called location determining unit for detecting a location of a called party from a location server including location information of a domain name server (DNS) or a SIP server based on the called party identification; A message generator for generating a response message including the identified called party location information; And And a second message transmitting unit which transmits the generated response message to the calling party. The method of claim 1, The SIP message is divided into a predetermined request message and a predetermined response message, The message receiving unit receives the response message in response to the request message, And the proxy server unit transmits the response message to the calling party that has sent the request message. The method of claim 5, The proxy server unit stores the header information of the request message when the request message is transmitted to the sender, and searches the stored header information based on the header information of the received response message to determine the location of the sender of the request message. SIP server, characterized in that to grasp. (a) receiving a SIP message including a called party identifier from the calling party; (b) setting a first mode performing a proxy server function and a second mode performing a redirect server function based on the type of the received message and the efficiency of the system; (c) identifying a location of the called party based on the called party identifier; (d) in the case of the first mode, transmitting the SIP message to the identified called party location; And (e) in the case of the second mode, transmitting the identified location information of the called party to the calling party. The method of claim 7, wherein The SIP message includes a predetermined request message and a predetermined response message. The step (b) comprises the step of setting a second mode if the SIP message is the request message and the system efficiency is greater than a predetermined reference value. The method of claim 7, wherein The step (c) includes determining a location of a called party using a location server including location information of a domain name server (DNS) or a called SIP server based on the called party identifier. SIP message processing method characterized in that. The method of claim 7, wherein The type of the SIP message is divided into a predetermined request message and a predetermined response message, Step (a) includes receiving a response message in response to the request message, The step (d) of the SIP message processing method comprising the step of transmitting the response message to the sender that sent the request message. The method of claim 7, wherein In step (e), (e1) generating a response message including the identified location information of the called party; And (e2) transmitting the response message to the identified calling party location. (a) receiving a SIP message including a called party identifier from the calling party; (b) outputting a mode setting signal for setting to a first mode performing a proxy server function and a second mode performing a redirect server function based on the type of the received message and the efficiency of the system; (c) identifying a location of the called party based on the called party identifier; (d) transmitting the SIP message to the identified called party location when the first mode setting signal is received; And (e) when receiving the second mode setting signal, transmitting the determined location information of the called party to the calling party; and recording a program for executing the SIP message processing method on a computer. Readable record carrier.